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United States Patent | 6,032,526 |
Akamatsu | March 7, 2000 |
A heating resistor type air flow-meter has a ratio-meter circuit comprising a proportional circuit for outputting a signal V.sub.out proportional to an input voltage V.sub.in a multiplying circuit for outputting a multiplied signal V.sub.m proportional to a product of a voltage difference VD between an internal reference voltage VINT and an external reference voltage VREF and the voltage signal V.sub.in and an adding circuit for adding the output signal V.sub.p of the proportional circuit and the output signal V.sub.m of the multiplying circuit.
Inventors: | Akamatsu; Masuo (Hitachinaka, JP) |
Assignee: | Hitachi, Ltd. (JP) |
Appl. No.: | 974393 |
Filed: | November 19, 1997 |
Nov 19, 1996[JP] | 8-307964 |
Current U.S. Class: | 73/204.17; 73/118.2; 73/204.15 |
Intern'l Class: | G01F 001/68 |
Field of Search: | 73/204.15,204.17,204.23,204.25,118.2 |
5201217 | Apr., 1993 | Wachi | 73/118. |
5537871 | Jul., 1996 | Itsuji et al. | 73/204. |
Foreign Patent Documents | |||
2-85724 | Mar., 1990 | JP. |